Dependable Fire Equipment Inc.
100 LeBaron Waukegan, IL 60085

Phone: 847 • 662 • 8400
Fax: 847 • 662 • 8420

Backflow Preventers

Water that is unable to transport through a cross-connection into public water system piping or through a consumer’s potable water system may causing it to reverse flow. The reverse in fluid flow result is called backflow. There are two kinds of backflow: backpressure backflow and backsiphonage.

An increase in downstream pressure, a reduction in the potable water system, or an instance of both can occur when the downstream pressure is greater than the potable water supply pressure (backpressure). Actions such as breaks in water mains, fire fighting, and water line flushing can cause the reduction in a potable water supply pressure. In these instances water is used in greater amounts than the available supplied water.

Backsiphonage
This occurs with there is negative pressure in public water systems or consumer potable water systems. A vacuum effect evidences when the normal flow of water supply is halted or slowed significantly from a break in a water main, fire fighting, or events requiring large usages of water.

Backflow Prevention
Backflow is prevented with an air gap using a mechanical backflow preventer. There are two kinds of mechanical preventers: Principal mechanical backflow preventers and a secondary mechanical backflow preventer.

Principal mechanical backflow preventers

Double check valve assembly

Pressure vacuum breaker assembly

Reduced-pressure principle assembly

Dependable Fire Equipment can test backflow preventers and ensure they are functional and sound using gauge equipment calibrated to check for air gaps. If a problem is found we can quickly remedy the situation.